Many devices exist for measuring the amount of fuel remaining in the fuel tank of a motor vehicle. Fuel level sensors for this purpose are typically either of an angular sweep type or a vertical sweep type. In the angular sweep fuel level sensor, a float is connected to one end of a pivoted float arm which rises or falls as the fuel level varies, while the other end of the float arm sweeps an arcuate path across a resistor element. In the vertical sweep fuel level sensor, the float travels linearly along a generally vertically disposed resistor element.
Both types of fuel level sensors are usually mounted for use by insertion through an access hole in the top or side of the fuel tank. Various assemblies have been proposed to ensure that the fuel level sensor, and the fuel pump it is often mounted with, are always in contact with the bottom of the fuel tank. For instance, U.S. Pat. No. 4,939,932 and U.S. Pat. No. 4,945,884 disclose constructions in which the lower end of the fuel level sensor assembly is urged against the bottom of the fuel tank. Because the shape and height of fuel tanks vary, however, a particular fuel level sensor design may not provide a float which is capable of traveling from the bottom to the top of the tank in all vehicles.
Fuel level sensors which are urged against the bottom of the fuel tank also often have a resulting angular orientation, which diminishes the resolution that is theoretically available. For example, the float arm of an angular sweep fuel level sensor may be restricted to something less than its full arc when the sensor is mounted at an angle to the bottom of the fuel tank. Furthermore, angular sweep fuel level sensors, which generally require more free working area than vertical sweep fuel level sensors, are susceptible to interference from deflatable bladders which are increasingly prevalent on motor vehicles.